1. Field of the Invention
The invention relates to a method for adjusting a positioning device that can be used in a vehicle, in particular an electric window opener, with regard to an end position. The invention also relates to a positioning device provided for carrying out the method.
2. Description of the Background Art
Motorized positioning devices are used in automotive engineering, in particular as motorized window openers. However, the invention also relates to positioning devices which are provided for the motorized adjustment of sunroofs, vehicle doors, seats or other vehicle components.
A conventional positioning device can include an electric positioning motor, which is coupled via a positioning mechanism to the vehicle component to be adjusted, i.e. in particular a vehicle window, in such a way that the vehicle component, which is hereinafter referred to as the positioning element, is movable along a predefined travel path between two end positions. In the case of a window opener, these end positions are predefined by the closed position and the open position of the vehicle window. The positioning mechanism of a positioning device of this type usually comprises a driving worm, coupled with the drive shaft of the positioning motor, as well as a worm gear that meshes therewith.
To equalize production tolerances and thus ensure that the window is always completely closed while the positioning device is in operation, at least the closed position is often not entirely predefined in the case of a window opener. Instead, the positioning device for the window opener is not adjusted to the closed position of the vehicle window until after the positioning device has been installed in the vehicle. With regard to this adjustment operation, this is also referred to as “training” the positioning device. For training purposes, the vehicle window is moved in the direction of the closed position until it is held in place against the vehicle body. The reaching of the closed position is detected by the fact that the positioning speed—or at least a measured variable that is characteristic thereof—comes to a stop. The closed position of the window determined in this manner is usually stored in a control unit of the positioning device. During normal operation, the window is usually stopped by the positioning device shortly before coming into contact with the vehicle body. However, the adjustment process described above is usually repeated regularly, for example after 50 load cycles in each case. The repeated adjustment of the positioning device is also referred to as “memorization”.
In some vehicle models, it is alternatively provided at the outset to have the positioning device always move the vehicle window to the limit stop.
If the window is moved to the limit stop, the mechanical stress transmitted from the vehicle body to the vehicle window is absorbed by the positioning device. As a result, the worm gear of the positioning mechanism, in particular, is placed under tension against the driving worm at a torque of typically up to 5-20 Nm. This stress may cause a deformation of the worm gear, which is usually made of plastic. This deformation may impair the functionality of the positioning device. In particular, a deformation of the worm gear may cause the positioning mechanism to run out of true. This, in turn, may impair further functionalities of the positioning device, for example the functionality of any automatic anti-trap control system that may be provided.